FR3058949A1 - VEHICLE SEAT SUSPENSION DEVICE - Google Patents

Abstract

Device (1) for suspending a first body (2) with respect to a second body (3), comprising - a damper (4) comprising a first chamber (13); a hydraulic jack (6) comprising a compression chamber (27); - a height regulator (5) comprising a cylindrical guide (22), a rod (21) slidably mounted, in a sealed manner, inside this cylindrical guide, the cylindrical guide being in hydraulic communication with the first chamber; of the damper, the cylindrical guide being, in addition, when the rod is at a first predetermined height (Hmin) of the cylindrical guide, in hydraulic communication with the compression chamber.

Description

Holder (s): PEUGEOT CITROEN AUTOMOBILES SA Société anonyme.

Extension request (s)

Agent (s): PEUGEOT CITROEN AUTOMOBILES SA Public limited company.

p4) VEHICLE SEAT SUSPENSION DEVICE.

FR 3 058 949 - A1 (57) Device (1) for suspending a first body (2) relative to a second body (3), comprising

- a shock absorber (4) comprising a first chamber (13);

- a hydraulic cylinder (6) comprising a compression chamber (27);

- a height regulator (5) comprising a cylindrical guide (22), a rod (21) slidingly mounted, in a sealed manner, inside this cylindrical guide, the cylindrical guide being in hydraulic communication with the first chamber of the damper, the cylindrical guide being, moreover, when the rod is at a first predetermined height (Hmin) of the cylindrical guide, in hydraulic communication with the compression chamber.

VEHICLE SEAT SUSPENSION DEVICE [0001] The invention generally relates to vehicle seat suspension devices, in particular motor vehicles, as well as to a motor vehicle equipped with such devices.

A vehicle seat is conventionally composed of a seat, carried by a support, in direct contact with the floor of the vehicle. This seat is sensitive to all the vibrations generated by the road behavior of the vehicle and which are transmitted to it by the floor.

Such vibrations, especially those of large amplitudes, have the effect of impacting not only the comfort of the occupants, but also the health and safety of the latter.

Seats aimed at damping vibrations of large amplitudes have been proposed, and are for example used for heavy goods vehicles or tractors. However, the architectures of these suspension devices are not compatible with the space available in a motor car.

In addition, the existing support devices for automobile car seats have limited power over all possible vibrations to which a seat may be subjected, in particular those of high amplitudes and / or high frequencies. Indeed, existing measurements of the characteristics of these non-suspended seats show that the driver's resonance frequency on his seat in the automotive field, for low frequency stresses, is of the order of 3 to 5 Hz. , however, that the viscerally unpleasant jump area is between 4 and 8 Hz. The unsprung seats of motor cars therefore have a limited filtering potential in jerks.

One objective is to provide a vehicle seat suspension device, in particular a motor car.

Another objective is to provide a suspension device for a motor car seat, allowing better filtering of the tremors.

Another objective is to provide a suspension device for a motor vehicle seat adaptable to the mass of the user.

Another objective is to provide a compact suspension device, so that it can be integrated into a wide variety of vehicles, in particular motor cars.

Another objective is to provide a suspension device incorporating, in addition, a damping function, and height regulation.

Another objective is to provide a device for suspending a first body relative to a second body, making it possible to filter out the vibrations of high amplitude from one relative to the other. Another objective is to provide a device for suspending a first body relative to a second body, incorporating a damper modulating the level of damping with the amplitude of relative movement between these two bodies.

To this end, it is proposed, firstly, a device for suspending a first body relative to a second body, comprising a damper, incorporating a first hollow cylinder, a first piston comprising a first rod and a first head fixed to a first end of this first rod, the first head being slidably mounted in the first hollow cylinder, so as to form, inside this first hollow cylinder, a first chamber located on the side opposite to the first rod and a second chamber through which this first rod passes, the second end of the first rod being intended to be integral with the first body, the first hollow cylinder being intended to be integral with the second body;

a hydraulic cylinder, comprising a second hollow cylinder and a second piston integrating a second rod and a second head fixed to a first end of the second rod, the second head being slidably mounted in the second hollow cylinder, so as to form, at the inside this second hollow cylinder, a compression chamber, the second end of the second rod being intended to be integral with the first body, the second hollow cylinder being intended to be integral with the second body;

a height regulator, comprising a cylindrical guide, a third rod mounted to slide, in a sealed manner, inside this cylindrical guide, the cylindrical guide being in hydraulic communication with the first chamber of the damper, the guide being cylindrical, moreover, when the third rod is at a first predetermined height of the cylindrical guide, in hydraulic communication with the compression chamber of the hydraulic cylinder.

Various additional characteristics can be provided, alone or in combination:

the hydraulic cylinder further comprises a first compensation chamber connected, via a calibrated non-return valve, to the compression chamber, the cylindrical guide being also, when the third rod is at a second predetermined height from the cylindrical guide , in hydraulic communication with the first clearing house;

- the compression chamber of the hydraulic cylinder is in hydraulic communication, via a calibrated non-return valve, with the first chamber of the damper;

- The first head of the first piston of the damper comprises a device for regulating the flow rate of a damping liquid from the first chamber to the second chamber and from the second chamber to the first chamber;

the second hollow cylinder of the hydraulic cylinder comprises a device for communicating the compression chamber with the cylindrical guide, this device for establishing communication comprising o a cylindrical body, comprising a first radial bore, an axial bore in communication with the first radial drilling;

o a cylindrical housing, comprising a second radial bore in communication with the compression chamber, the cylindrical body being slidably mounted, substantially perpendicular to the axis of the second hollow cylinder, in the cylindrical housing, so that, in a predetermined position of the cylindrical body in the cylindrical housing, the first radial hole is aligned with the second radial hole;

- The cylindrical body further comprises a lock, bevelled and projecting inside the second hollow cylinder, this lock being arranged on the stroke of the second head of the second piston, using a reminder;

the damper comprises a second compensation chamber, closed by a floating partition subjected to a means for maintaining pressure;

- the first compensation chamber is closed by a floating wall subjected to a means for maintaining a low pressure.

It is proposed, secondly, a vehicle comprising a seat, a floor and the suspension device as presented above, from the seat relative to the floor.

Other characteristics and advantages of the invention will appear more clearly and concretely on reading the following description of embodiments, which is made with reference to the appended drawings in which:

- Figure 1 schematically illustrates a suspension device according to various embodiments;

- Figure 2 schematically illustrates elements of the suspension device;

- Figure 3 is a perspective view of a motor car comprising a suspension device.

In Figure 1 is shown a device 1 for suspending a first body 2 relative to a second body 3. This suspension device 1 provides the suspension of the first body 1 relative to the second body 3, and dampens the relative oscillations between these two bodies 2 and 3, while controlling the minimum height Hmin and the maximum height Hmax between which these oscillations are damped.

For this, the suspension device 1 comprises a damper 4, a height regulator 5 and a hydraulic cylinder 6. The damper 4 comprises a hollow cylinder 7, arranged along an axis 8. This hollow cylinder 7 is filled with a damping liquid 9, such as, for example, oil. The hollow cylinder 7 is impermeable to the damping liquid 9. The hollow cylinder 7 is integral with the second body 3.

The damper 4 further comprises a piston 10. This piston 10 comprises a rod 11, arranged along the axis 8, and a head 12, fixed to a first end of this rod 11. The second end of the rod 11 leaves the hollow cylinder 7. The rod 11 is integral with the first body 2 via its second end.

The head 12 of the piston 10 is slidably mounted inside the hollow cylinder 7 along the axis 8, so as to form inside this hollow cylinder 7 a first chamber 13 located on the side opposite to the rod 11 and a second chamber 14 traversed by this rod 11. The exit of the rod 11 from the second chamber 14 comprises a guide and a dynamic seal, making it possible to close this second chamber 14.

The first chamber 13 and the second chamber 14 of the hollow cylinder 7 are located on either side of the head 12 of the piston 10 along the axis 8, so that when the piston 10 slides along the cylinder 7 hollow along axis 8, it compresses the damping liquid 9 contained in the first or second chamber 1314 depending on the direction of movement of this piston 10.

The damper 4 further comprises a compensation chamber 15. This compensation chamber 15 is in hydraulic communication with the first chamber 13. The compensation chamber is closed by a partition (or a wall) 16 floating, subjected to a means 17 for maintaining pressure. In one embodiment, the means 17 for maintaining pressure is a pressurized gas or a spring, making it possible to keep the damping liquid 9 in pressure in the compensation chamber 15. For example, a gas 17 under pressure makes it possible to continuously adjust the interior volume of the compensation chamber 15, as a function of the inlet or outlet of the damping liquid 9 from or to the first chamber 13 of the shock absorber 4.

During compression of the first chamber 13, at least part of the damping liquid 9 is discharged into the compensation chamber 15. Indeed, the excess damping liquid 9 expelled from the first chamber 13 and which cannot enter the second chamber 14, part of its volume of which is occupied by the rod 11, displaces the floating partition 16 downwards by compressing the means 17 for maintaining pressure.

Conversely, when the piston 10 slides towards the second chamber 14, the pressure maintenance means 17 (in particular, a pressurized gas) pushes back the floating partition 16, which in turn drives the liquid 9 from amortization to the first chamber 13.

Advantageously, a remote compensation chamber 15, as illustrated in FIG. 1, makes it possible to optimize the length of the shock absorber 4 and the stroke of the piston 10. Alternatively, the shock absorber 4 may comprise in the first chamber 13 an elastic end stop.

The head 12 of the piston 10 of the damper 4 comprises a first conduit 18 passing right through, so that the damping liquid 9 can flow from one chamber 13-14 to the other 1413 of the damper 4. In one embodiment, the first conduit is substantially parallel to the axis 8.

The head 12 of the piston 10 further comprises a second conduit 19 passing right through, so that the damping liquid 9 can flow from one chamber 13-14 to the other 14 -13 of the damper 4. In one embodiment, the second duct is substantially parallel to the axis 8. This second duct 19 comprises a device 20 for regulating the flow rate of the liquid 9 for damping a chamber 13-14 to another 14-13.

The flow control device 20 is configured to modify the damping coefficient of the shock absorber 4. For this, this flow control device comprises, in one embodiment, a mobile shuttle in a cavity arranged in the second conduit 19. This cavity, centered on the second conduit 19, is distant from the two ends of the second conduit 19 which open out, respectively, into the first chamber 13 and the second chamber 14 of the damper 4. The shuttle is mobile, in the cavity, between

- A closed position of the second conduit 19, called the hard position, in which the shuttle is close to or in contact with one of the ends of the second conduit 19, so that, during the sliding of the piston 10, the flow of the liquid 9 damping passing from one room 13-14 to another 14-13 is low and therefore generate significant damping; and

- An open position of the second conduit 19, called the soft position, in which the shuttle is distant from the ends of the second conduit 19, so that the flow of the damping liquid 9 passing from one chamber 13-14 to another 14-13 is stronger and therefore generates low depreciation.

Advantageously, the device 20 for regulating the flow gives the damper 4 a damping coefficient depending on the relative deflection frequency between the first body 2 and the second body 3. Being dependent on the stresses of the piston 10 of the damper 4, the movement of the shuttle of the device 20 for regulating the flow makes it possible, in effect, to modulate the flow of the damping liquid 9 flowing through the second conduit 19, so as to generate more damping at less important, depending on the position of the shuttle relative to the orifices of the second conduit 19. It is, of course, possible to choose a device 20 for regulating the flow rate which offers a damping law that best meets the comfort requirements required by the suspension device 1, for a certain use.

The height regulator 5 comprises a rod 21 slidingly mounted, in a sealed manner, inside a cylindrical guide 22. As illustrated in FIG. 1, the internal volume of the cylindrical guide 22 is of shape substantially complementary to that of the rod 21. The cylindrical guide 22 is arranged along the axis 8.

The height regulator 5 is integral, directly or indirectly (for example via the rod 11 of the piston 10 of the damper 4) by means of its rod 21, the first body 2.

The hydraulic cylinder 6 comprises a piston 23 incorporating a rod 24 and a head 25, fixed to one end of this rod 24. The other end of the rod 23 is integral with the rod 21 of the height regulator 5 (by example, via an interconnection means and via the first body 2). The head 25 of the piston 23 is slidably mounted in a hollow cylinder 26 along the axis 8. The head 25 of the piston 23 separates the volume of this hollow cylinder 26 into two chambers 27 and 28 isolated from each other:

a compression chamber 27, filled with the damping liquid 9 and located on the side opposite to the rod 24, and

- An expansion chamber 28, crossed by this rod 24. The end of the expansion chamber 28, opposite the head 28, is open.

A compensation chamber 29 is connected, via a calibrated non-return valve 30, to the compression chamber 27 of the hydraulic cylinder 6. The compensation chamber 29 is closed by a floating wall (or partition) 31, which is subjected to a means 32 for maintaining a low pressure (i.e. maintaining a pressure lower than that within the chamber 29 for hydraulic cylinder 6 compensation). In one embodiment, the means 32 for maintaining a low pressure is a gas under low pressure.

The calibrated non-return valve 30 has the function of authorizing the transfer of the damping liquid 9 between the compensation chamber 29 and the compression chamber of the hydraulic cylinder 6 only from the compensation chamber 29 to the compression chamber 27, in particular when the volume of the latter increases (ie when the piston 23 is biased towards the expansion chamber 28). In this case, the means 32 for maintaining a low pressure has the effect of retaining the damping fluid 9 in the compensation chamber 29, so as to slow the movement of the piston 28 towards the expansion chamber 28.

Advantageously, a remote compensation chamber 29, as illustrated in FIG. 1, has the advantage of avoiding an expansion stop to be placed in the main body of the hydraulic cylinder 6, for the purpose of make it more compact.

The hollow cylinder 26 and the rod 24 of the hydraulic cylinder 6 are, respectively, integral with the second body 3 and the first body 2. The compensation chamber 29 of the hydraulic cylinder 6 is in hydraulic communication, by the through a conduit 33, with the cylindrical guide 22 of the height regulator 5. The conduit 33 is connected to the cylindrical guide 22 via an orifice 34 located at a first height Hmax of the cylindrical guide 22.

The compression chamber 27 of the hydraulic cylinder 6 is in hydraulic communication, via a conduit 35, with the cylindrical guide 22 of the height regulator 5. The conduit 35 is connected to the cylindrical guide 22 via an orifice 36 located at a height Hmin from the cylindrical guide 22. The height Hmin is less than (or below) the height Hmax of the cylindrical guide 22.

The duct 35 is, moreover, connected to the compression chamber 27 of the hydraulic cylinder 6, via a device 37 for communication which will be presented below with reference to FIG. 2. The chamber 27 of compression of the hydraulic cylinder 6 is, moreover, in hydraulic communication, via a conduit 38, with the first chamber 13 of the damper 4. The conduit 38 connects the bottom of the chamber 27 of compression of the cylinder hydraulic 6 (ie the one opposite to the head 25 of the piston 23) at the bottom of the first chamber 13 of the damper 4 (ie the one opposite to the head 12 of the piston 10). The conduit 38 comprises a calibrated non-return valve 39, which authorizes the transfer of the damping fluid 9 only from the compression chamber 27 of the hydraulic cylinder 6 to the first chamber 13 of the damper 4, and not in the reverse.

The tared non-return valve 39 opens, under the effect of the pressure of the damping liquid 9 in the compression chamber 27, so as to allow its transfer to the first chamber 13 of the damper 4 .

The cylindrical guide 22 of the height regulator 5 is in hydraulic communication, via a conduit 40, with the first chamber 13 of the damper 4. In one embodiment, the fourth conduit 40 connects the bottom of the cylindrical guide 22 of the height regulator 5 at the bottom of the first chamber 13 of the damper 4.

The cylindrical guide 22 of the height regulator 5 is thus in hydraulic communication

- Via the conduit 35, with the compression chamber of the hydraulic cylinder 6, this communication taking place at a height Hmin of the cylindrical guide 22;

- Via conduit 33, with the chamber 29 for compensating the hydraulic cylinder 6, this communication taking place at a height Hmax of the cylindrical guide 22, the height Hmax being above Hmin;

- Via the conduit 40, with the first chamber 13 of the damper 4, this communication taking place at a height of the cylindrical guide 22 less than the height Hmin.

Referring to Figure 2, the communication device 37 comprises a cylindrical body 42 slidably mounted, substantially perpendicular to the axis of the hollow cylinder 26 of the hydraulic cylinder 6, in a cylindrical housing 43.

The cylindrical body 42 comprises an axial bore 44, in communication, on the one hand, with the conduit 35 and, on the other hand, with a radial bore 45. The cylindrical housing 43 comprises a radial bore 46 which, on the one hand, communicates with the compression chamber 27 of the hydraulic cylinder 6, and on the other hand, in an open position of the cylindrical body 42, with the radial bore 45 of this cylindrical body 42. This results in a permanent passage of the damping liquid 9, which can pass through the cylindrical body 42 and the cylindrical housing 43.

When the cylindrical body 42 is in the closed position, its radial bore 45 is not aligned with the radial bore 46 of the cylindrical housing 43. They are therefore not in communication. The cylindrical body 42 includes a latch 47 bevelled and projecting inside the compression chamber 27. This latch 47 is arranged protruding inside the hollow cylinder 26, on the stroke of the piston 23, using a return means such as a spring (not shown).

At rest, the cylindrical body 42 is in the closed position. In this case, the radial bore 45 of the cylindrical body 42 is not aligned with the radial bore 46 of the cylindrical housing 43, so that at rest there is no hydraulic communication between the cylinder compression chamber 27 6 hydraulic and the axial bore 44 of the cylindrical body 42, and consequently, no hydraulic communication, either, with the first chamber 13 of the damper 4.

By being projecting on its stroke, when the head 25 of the piston 23 of the hydraulic cylinder 6 comes into contact with the latch 47 of the cylindrical body 42, it pushes this latch 47, so as to align the radial bore 45 of the cylindrical body 42 on the radial bore 46 of the cylindrical housing 43. This results in the hydraulic communication of the compression chamber 27 with the first chamber 13 of the damper 4. This hydraulic communication occurs through the axial bore 44, the conduit 35, the cylindrical guide 22 and the conduit 40.

Referring again to FIG. 1, when the suspension device 1 is at rest (that is to say in the absence of relative oscillations between the first body 2 and the second body 3),

- the rod 21 (that is to say, its end introduced into the cylindrical guide 22) is at a height between the height Hmin and the height Hmax;

- the non-return valve 39 calibrated 33 is closed, so that the first chamber 13 of the damper 4 and the chamber 27 of compression of the hydraulic cylinder 6 are independent of one another, no transfer of the fluid 9 d 'Damping of the compression chamber 27 of the hydraulic cylinder 6 towards the first chamber 13 of the damper 4 is not possible;

the communication device 37 is in the closed position, preventing the transfer of the damping liquid 9 from the compression chamber 27 of the hydraulic cylinder 6 to the first chamber 13 of the damper 4;

- the orifice 34 is closed by the rod 21 of the height regulator 5, preventing hydraulic communication between the cylindrical guide 22 and the chamber 29 for compensating the hydraulic cylinder 6.

As a result, in this case, the compression chamber 27 of the hydraulic cylinder 6 and the first chamber 13 of the damper 4 are not in hydraulic communication

- nor directly via conduit 38;

- nor indirectly via the combination of duct 35, cylindrical guide 22 and duct 40.

When a request / vibration of small amplitude upwards according to arrow 40 or downwards according to arrow 41 is transmitted to the suspension device 1, and as long as the resulting deflection is between Hmin and Hmax, the configuration described above relating to the case of rest is retained. In other words, as long as the end introduced into the cylindrical guide 22 of the rod 21 of the height regulator 5 is between Hmin and Hmax (that is to say, the rod 21 is at a height between Hmin and Hmax of the cylindrical guide 22), no transfer of the damping liquid 9 is possible via the conduits 33 and 35. The compression chamber 27 of the hydraulic cylinder 6 and the first chamber 13 of the damper 4 remain independent l 'from one another (i.e. no exchange of damping liquid 9 between them).

In the case of a high amplitude bias upward along the arrow 51 of the suspension device 1, when the end introduced into the cylindrical guide 22 of the rod 21 of the height regulator 5 is above Hmax, the compensation chamber 29 of the hydraulic cylinder 6 and the first chamber 13 of the damper 4 become in hydraulic communication, via the conduit 33, the cylindrical guide 22 and the conduit 40. The damping liquid 9 can thus flow from the first chamber 13 of the damper 4 to the chamber 29 for compensating the hydraulic jack 6, via the conduit 40, the cylindrical guide 22 and the conduit 33.

The hydraulic communication of the chamber 29 for compensating the hydraulic cylinder 6 with the first chamber 13 of the damper 4 has the effect of making the stiffness of the hydraulic cylinder 4 constant, as well as changing the damping coefficient of the suspension device 1 in order to brake / absorb the oscillations. In the case of a high amplitude bias down, according to arrow 52 of the suspension device 1, the head 25 of the piston 23 of the hydraulic cylinder 6 comes into contact with the device 37 for communication, this which has the effect of triggering the hydraulic communication of the compression chamber 27 with the first chamber 13 of the damper. This hydraulic communication is established via the conduit 35, the cylindrical guide 22 and the conduit 40. The damping liquid 9 can thus flow from / to the first chamber 13 of the damper 4 towards / from the chamber 27 for compressing the hydraulic cylinder 6, passing through the conduit 40, the cylindrical guide 22 and the conduit 35.

Advantageously, the hydraulic communication of the compression chamber 27 of the hydraulic cylinder 6 has the effect of making the stiffness of the suspension device 1 constant, as well as modifying its damping coefficient, in order to brake / absorb the oscillations.

Consequently, when the end of the rod 21 of the height regulator 5 is not between the two orifices 34 and 36 (or, height interval [Hmin, Hmax]), the suspension device 1 has damping and stiffness coefficients different from those when the end of the rod 21 is between the orifices 34 and 36. By suitably choosing the positions of the orifices 34 and 36, representative of the two heights Hmin and Hmax on the guide 22 cylindrical (or equivalently the position of the device 37 for communication on the cylinder 26 of the hydraulic cylinder 6), and the stiffness of the calibrated check valves 30, 39, it is possible to obtain a damping law well suited to the relative movements between the first body 2 and the second body 3.

In one embodiment, the calibrated check valves 30 and 39 are identical, in order to obtain two identical damping laws for the two possible directions of stress. Tared non-return valves 30 and 39 of different characteristics can also be adopted, in order to obtain asymmetrical damping laws.

In a non-limiting embodiment illustrated in FIG. 3, the first body 2 is a seat 48 of a vehicle 49, in particular a motor car, and the second body 3 is the floor 50 of this vehicle 49. The suspension device 1 may be directly integral with the floor 50 of the vehicle or with intermediate elements such as two rails movable relative to the floor 50.

In this case, the rod 11 of the piston 10 of the damper 4 and the rod 24 of the piston 23 of the hydraulic cylinder 6 are secured, directly or via an interconnection, to the seat base 48 , while one end of the body of each of the two cylinders 7 and 26, respectively opposite to the rods 11 and 24, are integral, directly or indirectly, with the floor 50 of the vehicle 49.

When the rods 11 and 24 are stressed, the flow of the damping liquid 9 from one chamber 13-14 to another 14-13 of the damper 4 makes it possible to damp, according to a first law of damping, the relative oscillations, along the axis 8, between the seat 47 and the floor 50. As soon as the rod 21 of the height regulator 5 is at the height Hmin or at the height Hmax of the cylindrical guide 22, it is a new damping law and a new stiffness of the suspension device 1 which are implemented. This modification of the damping law and the stiffness occurs following the hydraulic communication (or, communication stop) of the first chamber 13 of the damper 4

- with the compression chamber 27 of the hydraulic cylinder 6, in the case of a travel up to Hmin; or

- with the chamber 29 for compensating the hydraulic cylinder 6, in the case of a travel up to Hmax.

The adaptation of the heights Hmin and Hmax as a function of the load on the seat 48 (ie, the stress on the suspension device 1) advantageously allows conductors of different masses to benefit from a same level of comfort.

In one embodiment, the suspension by means of the suspension device 1 described above is applied to the rear of the seat 48. In this case, a central shock absorber and / or two shock absorbers, respectively arranged on the right and to the left of seat 48 hinged around the anti-submarine bar, can be adopted.

In another embodiment, the suspension by means of the suspension device 1 described above is applied to the front (using, a central shock absorber and / or two shock absorbers arranged respectively to the right and to the left of the seat ) and at the rear of the seat 48 (using a central shock absorber and / or two shock absorbers arranged respectively to the right and to the left of the seat), the seat being completely suspended.

Of course, the seat 48 can be provided with other devices, such as a device for managing the inclination of the seat relative to the floor of the vehicle.

By arranging them in different places in the vehicle, the compensation chambers 15 and / or 29 occupy, advantageously, no space in the main body of the suspension device 1. More generally, the suspension device 1 described above can be interposed between two bodies 2 and 3, the relative oscillations of which are to be damped, and more particularly whose relative twitches are to be filtered.

Advantageously, the architecture of seat suspension described above allows better filtering of jerks by positioning the resonant frequency of the seat with its suspension at a frequency less than 3Hz.

Advantageously, the suspension device 1 described above makes it possible to dampen oscillations of high amplitudes, by filtering those generating a clearance below Hmin or above Hmax. This advantageously results in a correction of the deflection base. This correction has the effect of avoiding reaching a load position in the vicinity of the ends of the stroke of the piston 10 of the damper 4 and / or that of the piston 23 of the hydraulic cylinder 6. A correction of the deflection attitude also has the effect of avoiding any sudden impact resulting from an abrupt contact between the head 12 of the piston 10 of the damper 4 and the ends of the hollow cylinder 7 (or in an equivalent manner, from the head 25 of the hydraulic cylinder 6 and the ends of the hollow cylinder 26).

More generally, the suspension device 1 can be configured to filter only the deflections below the height Hmin of the height regulator 5, by removing the conduit 33. Similarly, the suspension device 1 can be configured to filter only the deflections above the height Hmax of the height regulator 5, by removing the duct 35.

Advantageously, the modulation of the level of damping with the amplitude of movement of the seat has the effect of moving the seat mode 48 from the mode of the floor 50 of the vehicle 49, so as to avoid the risk of excessive movements of the driver in his seat. The suspension device 1 described above has many advantages, and in particular allows

- to provide, thanks to the combination of the various elements described above, a compact seat suspension for several types of vehicle, in particular motor cars;

- to filter the oscillations of large amplitudes generated by the road behavior of a motor vehicle, while preserving from wear the mechanical parts which constitute the suspension device;

- offer several possibilities for development (the damping law of the device 20 for regulating the flow rate of the damping fluid 9, the positions of Hmin and Hmax on the height regulator 5, the stiffness of the valves 30, 39 tared non-return, the stiffness of the means 17 for maintaining pressure, the stiffness of the means 32 for maintaining a low pressure);

- to provide a combination of damping, suspension and height regulation functions.

Claims (10)

1. Device (1) for suspending a first body (2) relative to a second body (3), comprising - a shock absorber (4), incorporating a first hollow cylinder (7), a first piston (10) comprising a first rod (11) and a first head (12) fixed to a first end of this first rod (11), the first head (12) being slidably mounted in the first hollow cylinder (7), so as to form, inside this first hollow cylinder (7), a first chamber (13) located on the side opposite to the first rod (11) and a second chamber (14) through which this first rod (11) passes, the second end of the first rod (11) being intended to be integral with the first body (2), the first hollow cylinder (7) being intended to be secured to the second body (3); - a hydraulic cylinder (6), comprising a second hollow cylinder (26) and a second piston (23) integrating a second rod (24) and a second head (25) fixed to a first end of the second rod (24), the second head (25) being slidably mounted in the second hollow cylinder (26), so as to form, inside this second hollow cylinder (26), a compression chamber (27), the second end of the second rod (24) being intended to be integral with the first body (2), the second hollow cylinder (26) being intended to be integral with the second body (3); this device being characterized in that it further comprises - A height regulator (5) comprising a cylindrical guide (22), a third rod (21) slidingly mounted, in a sealed manner, inside this cylindrical guide (22), the cylindrical guide (22) being in hydraulic communication with the first chamber (13) of the damper (4), the cylindrical guide (22) being, moreover, when the third rod (21) is at a first predetermined height (Hmin) of the guide (22) cylindrical, in hydraulic communication with the chamber (27) for compression of the hydraulic cylinder (6). 2. Suspension device (1) according to claim 1, characterized in that the hydraulic cylinder (6) further comprises a first compensation chamber (29) connected, via a calibrated non-return valve (30), to the chamber (27) compression, the cylindrical guide (22) being further, when the third rod (21) is at a second predetermined height (Hmax) of the cylindrical guide (22), in hydraulic communication with the first chamber (29) compensation. 3. Suspension device (1) according to claim 1 or 2, characterized in that the compression chamber (27) of the hydraulic cylinder (6) is in hydraulic communication, via a calibrated non-return valve (39), with the first chamber (13) of the shock absorber (4). 4. Suspension device (1) according to any one of the preceding claims, characterized in that the first head (12) of the first piston (10) of the damper (4) comprises a device (20) for regulating the flow passage of a damping liquid (9) from the first chamber (13) to the second chamber (14) and from the second chamber (14) to the first chamber (13). 5. Suspension device (1) according to any one of the preceding claims, characterized in that the second hollow cylinder (26) of the hydraulic cylinder (6) comprises a device (37) for placing the chamber (27) in communication. compression with the cylindrical guide (22), this communication device (37) comprising - a cylindrical body (42), comprising a first radial bore (45), an axial bore (44) in communication with the first radial bore (45); - a cylindrical housing (43), comprising a second radial bore (46) in communication with the compression chamber (27), the cylindrical body (42) being mounted to slide, substantially perpendicular to the axis of the second hollow cylinder (26) , in the cylindrical housing (43), so that, in a predetermined position of the cylindrical body (42) in the cylindrical housing (43), the first radial bore (45) is aligned with the second radial bore (46). 6. Suspension device (1) according to the preceding claim, characterized in that the cylindrical body (42) further comprises a latch (47) bevelled and projecting inside the second cylinder (26) hollow, this lock (47) being disposed on the stroke of the second head (25) of the second piston (23), using a return means. 7. Suspension device (1) according to any one of the preceding claims, characterized in that the damper (4) 5 comprises a second compensation chamber (15). 8. Suspension device (1) according to the preceding claim, characterized in that the second compensation chamber (15) is closed by a floating partition (16) subjected to a means (17) for maintaining pressure. 10 9. Device (1) for suspension according to any one of claims 2 to 8, characterized in that the first compensation chamber (29) is closed by a floating wall (31) subjected to a holding means (32) low pressure. 10. Vehicle (49) comprising a seat (48), a floor (50), 15 characterized in that it further comprises a device (1) for suspending the seat (48) relative to the floor (50) according to any one of the preceding claims. 1/3